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BUG: KCSAN: data-race in calc_timer_values / perf_event_update_time

write to 0xffff888120ebecc8 of 8 bytes by task 12798 on cpu 1:
 __perf_update_times kernel/events/core.c:631 [inline]
 perf_event_update_time+0x183/0x200 kernel/events/core.c:638
 perf_event_set_state.part.0+0x4a/0x100 kernel/events/core.c:657
 perf_event_set_state kernel/events/core.c:654 [inline]
 event_sched_out kernel/events/core.c:2101 [inline]
 event_sched_out.isra.0+0x228/0x540 kernel/events/core.c:2073
 group_sched_out.part.0+0x5c/0x140 kernel/events/core.c:2127
 group_sched_out kernel/events/core.c:2122 [inline]
 ctx_sched_out+0x568/0x5a0 kernel/events/core.c:3059
 task_ctx_sched_out+0x59/0x90 kernel/events/core.c:2500
 perf_event_context_sched_out kernel/events/core.c:3234 [inline]
 __perf_event_task_sched_out+0x544/0xaa0 kernel/events/core.c:3325
 perf_event_task_sched_out include/linux/perf_event.h:1167 [inline]
 prepare_task_switch kernel/sched/core.c:3157 [inline]
 context_switch kernel/sched/core.c:3336 [inline]
 __schedule+0x407/0x690 kernel/sched/core.c:4078
 preempt_schedule_irq+0x57/0x90 kernel/sched/core.c:4328
 restore_regs_and_return_to_kernel+0x0/0x25
 __read_once_size+0xd/0x80 include/linux/compiler.h:227
 slab_pre_alloc_hook mm/slab.h:572 [inline]
 slab_alloc mm/slab.c:3305 [inline]
 kmem_cache_alloc_trace+0x112/0x5d0 mm/slab.c:3548
 kmalloc include/linux/slab.h:556 [inline]
 kzalloc include/linux/slab.h:690 [inline]
 alloc_pipe_info+0xa8/0x330 fs/pipe.c:659
 splice_direct_to_actor+0x485/0x510 fs/splice.c:917
 do_splice_direct+0x161/0x1e0 fs/splice.c:1063
 do_sendfile+0x384/0x7f0 fs/read_write.c:1464
 __do_sys_sendfile64 fs/read_write.c:1519 [inline]
 __se_sys_sendfile64 fs/read_write.c:1511 [inline]
 __x64_sys_sendfile64+0xbe/0x140 fs/read_write.c:1511
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888120ebecc8 of 8 bytes by task 12928 on cpu 0:
 __perf_update_times kernel/events/core.c:629 [inline]
 calc_timer_values+0x114/0x1d0 kernel/events/core.c:5340
 perf_event_update_userpage+0x7b/0x340 kernel/events/core.c:5395
 perf_mmap+0xe00/0xeb0 kernel/events/core.c:5877
 call_mmap include/linux/fs.h:1900 [inline]
 mmap_region+0x83c/0xd50 mm/mmap.c:1806
 do_mmap+0x6d4/0xba0 mm/mmap.c:1577
 do_mmap_pgoff include/linux/mm.h:2348 [inline]
 vm_mmap_pgoff+0x12d/0x190 mm/util.c:496
 ksys_mmap_pgoff+0x2d8/0x420 mm/mmap.c:1629
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline]
 __x64_sys_mmap+0x91/0xc0 arch/x86/kernel/sys_x86_64.c:91
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 12928 Comm: syz-executor.4 Not tainted 5.4.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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